Conversion of hydrocarbons



Oct. 26, 1943. G. EGLOFF CONVERSION OF HYDROCARBONS Filed NOV. 22, 1940 HYDROCARBON OIL CHARGING STOCK ,2 I CATALYTIC CRACKING ZONE H LIGHT GASES REsmu r RICH m HYDROGEN .L SEPARATION 32 5 |2\-. 7 3 l5 H c; FRACTIONS -C4 OR THERMAL GASOLINE ca 8.0 CRACKING FRACTIONS ZONE 1 CATALYTIC v CATALYTIC LIQUID POLYMER- POLYMER- IZATION IZVATION l7 UNCONVERTE 26 /27 Y c FRACTIONS UNCONVERTED 25 PROPANE a. YBUTANE SEPARATION POLYMER w GASOLINE HEAVY POLYMERS v V E 3 f Y r I V 29 CATALYTIC I SEPARATION HYDROGEN- *ATION HEAVY ZONE POLYMERS 33 POLYMER (34 GASOLINE as SEPARATION HEAVY 35 gig 22m HYDROGENATED |NVENTQR POYLMERS HYDROGENATED POLYMER GUSTAV EGLOFF' GASOLINE v (ISO-OCTANES) E BY ATTORNEY I Patented Got. 26, 1943 PATENT OFFICE oomnsron or nrpnocannons Gustav Eglofl, Chicago, 111., assignor to Universal Oill'roducts company, Chicago, 111., a corporation of Delaware Application November 22, 1940, Serial No. 366,679

4 Claims. (Cl. 196-9) The invention relates to an improved process involving the catalytic cracking of hydrocarbon oil, catalytic polymerization of,heavy olefin-contaming gases and the thermal cracking treatment of unconverted parafllnic components of the gases 5 subjected to said catalytic polymerization in commingled state with intermediate liquid conversion products of the process, the various steps being combined in an interdependent and cooper- I ative manner which results in the production ofhigh yields of good antlknock gasoline.

Inaccordance with one specific embodiment of the invention, a hydrocarbon oil suitable for catalytic cracking treatment, to produce therefrom high yields of good antiknock gasoline and gases rich in hydrogen and polymerizable olefinic hydrocarbons, is subjected to such cracking treatment in commingled state with light hydrogencontaining gases produced within the system. The resulting vaporous and gaseous conversion products are fractionated and separated into stabilized, gasoline of the-desired 'vapor pressure, heavier liquid conversion products suitable for rich in hydrogen and heavier normally gaseous fractions rich in polymerizable oleflns. Regulated quantities of said hydrogen-containing gases finic components of the gases subjected to said polymerization treatment. Said unconverted par-amps are commingled with said intermediate liquid conversion products. the resulting mixture subjected to vapor-phase thermal cracking treat- 40 ment to produce additional high yields of good antiknock gasoline and oleiinio gases and the resulting products of the thermal cracking step are commingled with the products of the catalytic cracking step prior to said fractionation of the vaporou and gaseouscomponents of the latter.

The composition of the relatively light gases returned to the catalytic cracking step, with respect to the inclusion therein of fractions boilin above hydrogen, may be regulated to suit requirements as may the composition of the heavy gases subjected to polymerization, with respect to the proportion of C3 and 04 fractions included therein Any suitable well known cracking catalyst may be employed for promoting catalytic crackin treatment of the charging oil and this step, may,

I for example, be of the type employing a fixed bed or beds of granular catalyst orof the type wherein finely divided or powdered catalytic material isv 7 included in the flowing stream of hydrocarbon oil or vapors undergoing the catalytic cracking treatment.

Any suitable well known polymerizing agent, such as the type now generally known in the art as solid phosphoric acid, acid treated clays and the like or liquid phosphoric or sulfuric acid may be employed in the polymerizingstep of the system and the butylene produced within the system may be subjected to polymerization treatment thermal cracking treatment, relatively 118m; gases 2, each well known per se and the invention resides in the novel and advantageous manner in which they are cooperatively combined.

The accompanying drawing is essentially a flow diagram illustrating one specific embodiment of the process herein provided and various alternative modes of operation which are also within the scope of the invention.

Referring to the drawing, the hydrocarbon oil charging stock for the process, which maybe any oil amenable to catalyticcracking, is supplied Resulting conversion products are supplied from the catalytic crackingstep through line 3 to separation in zone I which preferably comprises fractionating, condensing and collecting equipment of any suitable'conventional form and which may include conventional equipment for stabilizing the gasoline and absorption equipment for effecting good separation between the desired light and heavy normally. gaseous fractions.

Anyheavy liquid conversion products unsuitable ascharging oil for the subsequent thermal cracking step are removed from, the system .treatment' conducted in zone through line 5. Gasoline of the desired end-boiling point and vapor pressure is removed from the system to storage or to any desired further treatment through line 6. Intermediate liquid conversion products suitable for thermal cracking treatment are supplied through lines I and 8 to the thermal cracking step 9, which will be later described. Relatively light hydrocarbon gases and hydrogen are directed from the separating zone through line H) and may be,,a1l or in part, removed from the system through this line or they may be returned in regulated quantities through line II to the catalytic cracking step wherein the presence of hydrogen and light hydrocarbon gases are beneficial and/or regulated quantities or the hydrogen-containing gases may be directed from line In through line l2 to the catalytic hydrogenating step 23, when the latter is employed.

Higher boiling normally gaseous products, consisting predominantly of fractions having 3- and 4-carbon atoms in the molecule and which are rich in the readily polymerizable oleflns, propylene and butylenes, are directed from separating zone 4 to catalytic polymerization treatment for conversion of the oleflns into high yields of liquid polymers boiling within the range of gasoline and of good antiknock value.

It is within the scope of the invention to subject the Grand C4 gases to polymerization in commingled state or to separate the same and subject the separate fractions to separate polymerization treatment. Two catalytic polymerizing steps H and I6 are, therefore, illustrated in the drawing, although only one need be employed when the C: and C4 gases are subjected to mixed polymerization treatment. In the latter case, the C: and C4 fractions are directed in commingled state from zone 4 through line l3 to the catalytic polymerization step ll wherein they are contacted under suitable temperature andpressure conditions with an active cracking catalyst, such as, for example, solid phosphoric acid and wherein they are converted into mixed polymers which result from polymerization of substantially all of the iso and normal butylenes, as well as substantial quantities of. the propylene.

when both polymerizing steps are employed, substantially only the C4 fractions are supplied to zone H, the Ca fractions being separately removed from zone 4 and supplied through line E to catalytic polymerizing step It. In such instances, the catalyst and conditions of operation employed in zone I are preferably regulated to effect substantially complete conversion of the iso-butylene fractions supplied thereto with a limited amount or substantially no conversion of the normal butylene fractions; Sulfuric acid is more selective as a polymerizing catalyst to isobutylene than phosphoric acid and with a sulfuric acid catalyst, conditions may be regulated to substantially preclude polymerization of normal butylene. With proper control of the conditions of temperature pressure and contact time, phosphoric acid may also be used for relatively selective polymerization of the isobutylene, but normally with this catalyst some of the normal butylene will also be converted.

The products of the catalytic polymerization I4 are directed therefrom through line H to separating zone I8 which may comprise fractio'nating equipment of any suitable well known form and may include conventional equipment for stabilizing the polymer gasoline-i Heavy polymers, such'as those for stabilizing the polymer gasoline.

boiling above the range of gasoline, are removed from the separating zone l8 and from the system through line IS. The polymer gasoline is directed from zone l8 through line 20 and may be removed, all or in part, from the system to storage or elsewhere, as desired, through line 2! or, preferably, is directed through line 22 to a catalytic hydrogenating step 23, which will be later described. r

The normally gaseous fractions which remain unconverted in polymerizing zone H are removed from the separating zone l8 through line 25 and, depending upon the nature of the polymerization treatment in zone M, may be supplied through lines 25 and 8 to thermal cracking treatment in -zone 8, together with the intermediate liquid conversion products from zone or they may be directed from line 23 through lines 23 and i5 to further polymerization treatment in zone 15. When the mixed polymerization of C3 and Ci olefins is accomplished in zone M, the unconverted gases will consist predominantly of Ca and C4 parafiins and are directed, as previously described, from zone 58 to the thermal cracking step 9. When the selective polymerization of butylene is accomplished in zone it, the unconverted gases will include both butanes and normal butylene and are preferably directed, as previously described, to polymerizing zone 66.

The normally gaseous fractions supplied to zone l6 are therein conducted under suitable temperature and pressure conditions with a polymerizing catalyst capable of converting both the normal butylene and the propylene into high yields of polymer gasoline of good antiknock value. The resulting conversion products are directed from zone l6 through line 21 to separating zone 28 which may comprise fractionating equipment of any suitable well known form and which may, when desired, include equipment Heavy polymers, such as those boiling above the range of the desired polymer gasoline, are removed from zone 28 and from the system through line thermal cracking treatment in zone 9, together with the intermediate liquid conversion products supplied to this zone, as previously described, from separating zone 4.

The thermal cracking treatment afforded the mixture of intermediate liquid conversion products and essentially paraflinic gases in zone 9 is of a nature regulated to produce additional high yields of good anti-knock gasoline from said intermediate liquid conversion products and efiect substantial dehydrogenation of the parafflnic gases to form corresponding olefins and hydrogen. Preferably, substantially vapor-phase cracking conditions are employed in zone 9. The resulting products, in addition to hydrogen, readily polymerizable normally gaseous olefins and gasoline, will include residual liquid, intermediate liquid conversion products and other gases. These products are directed from zone 9 through line 32 to separating zone 4 wherein they are subjected to the same separation as that afforded the conversion products from the catalytic cracking steps with which they are commingled in this zone.

, The catalytic hydrogenating step of the system is optional. It is preferably employed, however, when the selective polymerization of iso-- butylenes is accomplished in zone I since, with the high degree of selectivity in this .zone, the resulting liquid polymers will consist largely of iso-octenes which may advantageously be hydrogenated to produce iso-octanes of improved antiknock value. Any suitable hydrogenating catalyst, such as nickel oxide, forexample, may be employed in zone 23 for efiecting hydrogenation of the polymer gasoline and the hydrogen required for this type is preferably derived from the catalytic cracking and dehydrogenating steps of the system, provision being made, as previously described, for supplying hydrogen-containing gases irom'zone 4 to zone 23.

The hydrogenated polymers ,are directed from which may comprise fractionating equipment of any suitable well known form. l-Iydrogenated polymers of the desired boiling range,'which consists principally of iso-octanes, are directed from zone 34 through line 35 to storage or elsewhere, as desired. Any heavier products of the hydrogenating steps which would tend to contaminate and increase the antiknock value of the essentially iso-octane product are removed fromzone 36 and from the system through line 36. Normally gaseous fractions rich in hydrogen are removed from zone 33 through 'line3l and may be discharged, all or in part, from the system through this line but, preferably, regulated quantities of these hydrogen-containing gases" are recycled through line 38 tothe hydrogenating zone for further use, a substantial excess of hydrogen over that theoretically required for complete hydrogenation of the polymers being maintained in this step.

"As an example of one specific operation of the process, the charging stock is a gas oil of approximately 32 A. P. I. gravity derived from mixed base crude, fixed. beds of granular catamately 30 pounds per square inch as measured at the outlet from the catalyst reactors and with a space velocity, expressed as volume of oil treated, per hour, per unit volume of spac oc-,

cupied' by the catalyst bed, of approximately 3. Separate polymerizing steps are employed, one

for converting iso-butylenes and a substantially.

equal molal proportion of normal butylenes into liquid polymers rich in octenes and the other for converting residual normal butylenes from the first step and propylenes into mixed polymers boiling within the range of gasoline. Both steps 7 employ flxed beds of solid phosphoric acid catazone 23'through line 33 to separating zone 34 ployed as a catalyst. The hydrogenating step is operated at a superatmosphericpressureof approximately 250 pounds per square inch and at a temperature 01' 350 F. The resulting hydrogenated polymers, which are rich-in iso-octanes,

are recovered and the polymer gasoline resulting from the mixed polymerization step is separately recovered.

Unconverted propane and butane from the two polymerizing steps are supplied, together with intermediate liquid conversion products formed in I the catalytic and thermal cracking steps, to the ing step are supplied.

In an operation,-such as above described, one may obtain perbarrel of gas oil charging stock,

approximately 58 volumeof cracked gasoline comprising a mixture of that produced in the catalytic cracking step and that produced in the thermal cracking'step and having an end-boil-' ing point of approximately 425 l5. andan octane number of approximately 75. 'The mixed polyrner gasoline produced may amount to approxilyst, the selective polymerizing operation being conducted at a temperature .of approximately 300 F. and a superatmospheric pressure 'of about rnerizirig, step is catalytically hydrogenated, uti- .lizing gases rich in hydrogen derived from the catalyti ence c-aird, thermal cracking steps in the pres- "tionary beds of reduced nickel emmately 3.4 gallons per barrel of charging oil supplied to the catalytic cracking step and the hydrogenated polymer product may amount to approximately 2.4 gallons per barrel of gas oil charging stock.

It will, of course, be understood that the invention is not limited. to the particular mode of operation described in the foregoing specific'example nor to the operating conditions for each of the steps specifiedtherein; since several alternative modes of operation have been,illustrated and described and it is within the knowledge of one skilled in the art to determine optimum operating conditions in each of the various steps, which conditions will vary with the specific mode of operation employed, as well as thenature of the chargingstock, catalysts and the desired nature of the products.

I claim as my invention;

1. The process of converting hydrocarbons to produce therefrom high yields of good antiknock gasoline,.which comprises cracking a straightrun hydrocarbon oil in'the presence of a siliceous cracking catalyst, separating from the resulting vaporous and gaseous products gasoline of the desired end-boiling point and vapor pressure, higher boiling liquid fractions suitable for thermal cracking treatment, high-boiling normally gaseous fractions rich in readily polymerizable oleflns and lower boiling gases rich in hydrogen, returning regulated quantities of the latter to the catalytic cracking step, recovering said gasoline, subjecting said high-boiling normally gaseous fractions to polymerization to convert ole-' flnic components'thereof into substantial yields of liquid polymers boiling within the range of gasoline and of good antiknock value, commingling unconverted paraflinic components of the highboiling gases subjected to said polymerization with said higher boiling liquid fractions, thermally cracking the mixture in essentially vaporous state under conditions regulated toproduce therefrom substantial additional yields of good antiknock gasoline and readily polymerizable olefinic gases and commingling resulting vaporous and gaseous products of the thermal cracking step with the products ofthe catalytic cracking step prior to said separation of the vaporous and gaseous components of the latter.

2. The process of converting hydrocarbons which comprises, catalytigally cracking a virgin hydrocarbon oil charging" stock to produce therefrom high yields of good antiknock gasoline, higher boiling liquid fractions and normally gaseous fractions rich in readily polymerizable olefins and hydrogen, separating from resulting vaporous and gaseous conversion products gasoline of the desired end-boiling point and vapor pressure, higher boiling normally liquid fractions, normally gaseous fractions consisting predominantly of butanes and butylenes, normally gaseous fractions consisting predominantly of propane and propylene and a lower boiling gaseous fraction rich in hydrogen, returning the latter in regulated quantities to the catalytic cracking step, recovering said gasoline, catalytically polymerizing olefinic components of said butane-butylene fractions to produce therefrom substantial yields of liquid polymers boiling within the range of gasoline and of good antiknock value, separately subjecting said'propaneepropylene fractions to catalytic polymerization treatment to produce therefrom substantial yields of liquid polymers boiling within the range of gasoline of good antiknock value, separately recovering the polymer gasolines produced inthe separate polymerizing steps, commingled unconverted propane and unconverted butanes from the polymerizing steps with said higher boiling liquid fractions, thermally cracking the resulting mixture in essentially vaporous state to produce therefrom additional high yields of good antiknock gasoline and additional quantities of propylene and butylenes and commingling resulting vaporous and gaseous products of the thermal cracking step with the products of the catalytic cracking step prior to said separation of the vaporous and gaseous components of the latter.

3. The process of converting hydrocarbons which comprises, catalytically cracking a virgin butylene fractions to catalytic polymerization treatment to convert principally their iso-butylene components into liquid polymers consisting principally of iso-octenes, catalytically hydrogenating the latter to produce iso-octanes and recovering the same, commingling unconverted butanes and normal butenes from said polymer izing step with said propane-propylene fractions, subjecting the mixture to catalytic polymerization treatment to convert a major portion of its olefinic components into liquid polymers of high antiknock value boiling within the range of gasoline, recovering the latter, commingling unconverted propane and butanes from the second mentioned polymerizing step with said higher boiling liquid fractions, thermally cracking the mixture in essentially vaporous state to produce therefrom substantial additional yields of good antiknock gasoline and additional quantities of propylene and butylenes and commingling resulting vaporous and gaseous products of the thermal cracking step with the products of the catalytic cracking step prior to said separation of the vaporous and gaseous components of the latter.

4. The process of converting hydrocarbons which comprises, catalytically cracking a virgin hydrocarbon oil charging stock to produce therefrom high yields of good antiknock gasoline, higher boiling liquid fractions and normally gaseous fractions rich in readily polymerizable olefins and hydrogen, separating from resulting vaporous and gaseous conversion products gasoline of the desired end-boiling point and vapor pressure, higher boiling normally liquid fractions, normally gaseous fractions consisting predominantly oi propylene-butylenes and the corresponding paraflns and a lower boiling gaseous fraction rich in hydrogen, returning the latter in regulated quantities to the catalytic cracking step, recovering said gasoline, subjecting the first named normally gaseous fractions to catalytic polymerization treatments to eilect the mixed polymerization of propylene and butylenes into substantial yields of liquid polymers of good antiknock value boiling within the range of gasoline, recovering the latter, commingling unconverted paraflinic gases from the polymerizing step with said higher boiling liquid fractions, subjecting the mixture to thermal cracking treatment in essentially vaporous state to produce therefrom additional high yields of good antiknock gasoline and substantial additional quantities of propylene and butylenes and commingling resulting prod- .ucts of thermal cracking ,step with the products of the catalytic cracking step prior to said separation of the vaporous and gaseous components of the latter.

GUSTAV EGLOFF. 

